Finalize exercises in your book:
P. 50 --> EX. 3
P. 51 --> EX. 2- 3
P. 55 --> EX 6 - 7 - 8 - 9
P. 61 --> EX 14 - 15 -16 - 17 -18
P. 64 --> EX 19 - 20
P.68 --> EX. 21 - 22
P.72 --> EX. 29 -30 -31
P.78 --> EX. 39
P.80 -- > EX. 41 - 42 - 43
P.82 --> EX. 44 - 45 - 46